Radish

Radishes are a slightly more finicky annual, very susceptible to heat and drought. Note that Daikons are biennial, and thus must be treated more like a turnip when growing for seed.

Germination
Plant in full sun or partial shade, at a depth of 0.5". Radishes germinate at soil temperatures of 45-85° F. Sow outdoors in the spring, in rows one foot apart. Thin to two inches.

Pollination
Radishes are cross-pollinated by bees.

As all varieties of radish wild and domestic are members of the same species it is possible for them to cross-breed, but they will not hybridize with other members of Brassicaceae. If hand-pollinating it should be noted that the plants cannot self-pollinate. The pollen of one plant must be transferred to the flower of a separate plant in order to produce viable seed.

Seed Collection
      Once radishes are large enough to eat, remove and inspect them. Judge based on size, shape, and color, and eat those that don't meet your standards. Give your pretty radishes a haircut: leave only one inch of leaf on top, being careful not to cut the small central leaves. Replant them eight inches apart in rows three feet apart. Wait seed pods are brown, then open by hand to collect the seeds.        It is possible to skip the pulling, inspecting, and replanting of your radishes, but the resulting seed will yield less uniform plants.        You may find the pods hard to open by hand. Gently hammering with a wooden mallet is recommended to help crack the shells.